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Patel L, Singh R, Gowd SC, Thottathil SD. Environmental determinants of aerobic methane oxidation in a tropical river network. WATER RESEARCH 2024; 265:122257. [PMID: 39178592 DOI: 10.1016/j.watres.2024.122257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 07/08/2024] [Accepted: 08/12/2024] [Indexed: 08/26/2024]
Abstract
Aerobic methane oxidation (MOX) significantly reduces methane (CH4) emissions from inland water bodies and is, therefore, an important determinant of global CH4 budget. Yet, the magnitude and controls of MOX rates in rivers - a quantitatively significant natural source of atmospheric CH4 - are poorly constrained. Here, we conducted a series of incubation experiments to understand the magnitude and environmental controls of MOX rates in tropical fluvial systems. We observed a large variability in MOX rate (0.03 - 3.45 μmol l-1d-1) shaped by a suit of environmental variables. Accordingly, we developed an empirical model for MOX that incorporate key environmental drivers, including temperature, CH4, total phosphorus, and dissolved oxygen (O2) concentrations, based on the results of our incubation experiments. We show that temperature dependency of MOX (activation energy: 0.66 ± 0.18 eV) is lower than that of sediment methanogenesis (0.71 ± 0.21 eV) in the studied tropical fluvial network. Furthermore, we observed a non-linear relationship between O2 concentration and MOX, with the highest MOX rate occuring ∼135 μmol O2l-1, above or below this "optimal O2" concentration, MOX rate shows a gradual decline. Together, our results suggest that the relatively lower temperature response of MOX compared to methanogenesis along with the projected decrease of O2 concentration due to organic pollution may cause elevated CH4 emission from tropical southeast Asian rivers. Since estimation of CH4 oxidation is often neglected in routine CH4 monitoring programs, the model developed here may help to integrate MOX rate into process-based models for fluvial CH4 budget.
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Affiliation(s)
- Latika Patel
- Department of Environmental Science and Engineering, SRM University-AP, Amaravati, Andhra Pradesh 522 502, India
| | - Rashmi Singh
- Department of Environmental Science and Engineering, SRM University-AP, Amaravati, Andhra Pradesh 522 502, India
| | - Sarath C Gowd
- Department of Environmental Science and Engineering, SRM University-AP, Amaravati, Andhra Pradesh 522 502, India
| | - Shoji D Thottathil
- Department of Environmental Science and Engineering, SRM University-AP, Amaravati, Andhra Pradesh 522 502, India.
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2
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Yao X, Wang J, He M, Liu Z, Zhao Y, Li Y, Chi T, Zhu L, Zheng P, Jetten MSM, Hu B. Methane-dependent complete denitrification by a single Methylomirabilis bacterium. Nat Microbiol 2024; 9:464-476. [PMID: 38228857 DOI: 10.1038/s41564-023-01578-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 12/08/2023] [Indexed: 01/18/2024]
Abstract
Methane-dependent nitrate and nitrite removal in anoxic environments is thought to rely on syntrophy between ANME-2d archaea and bacteria in the genus 'Candidatus Methylomirabilis'. Here we enriched and purified a single Methylomirabilis from paddy soil fed with nitrate and methane, which is capable of coupling methane oxidation to nitrate reduction via nitrite to dinitrogen independently. Isotope labelling showed that this bacterium we name 'Ca. Methylomirabilis sinica' stoichiometrically performed methane-dependent complete nitrate reduction to dinitrogen gas. Multi-omics analyses collectively demonstrated that 'M. sinica' actively expressed a well-established pathway for this process, especially including nitrate reductase Nap. Furthermore, 'M. sinica' exhibited a higher nitrate affinity than most denitrifiers, implying its competitive fitness under oligotrophic nitrogen-limited conditions. Our findings revise the paradigm of methane-dependent denitrification performed by two organisms, and the widespread presence of 'M. sinica' in public databases suggests that the coupling of methane oxidation and complete denitrification in single cells substantially contributes to global methane and nitrogen budgets.
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Affiliation(s)
- Xiangwu Yao
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental Resource Sciences, Zhejiang University, Hangzhou, China
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
| | - Jiaqi Wang
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
| | - Mingyue He
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
| | - Zishu Liu
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental Resource Sciences, Zhejiang University, Hangzhou, China
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
| | - Yuxiang Zhao
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
| | - Yufen Li
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
| | - Taolve Chi
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
| | - Lin Zhu
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
| | - Ping Zheng
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental Resource Sciences, Zhejiang University, Hangzhou, China
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
| | - Mike S M Jetten
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences (RIBES), Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Baolan Hu
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental Resource Sciences, Zhejiang University, Hangzhou, China.
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.
- Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou, China.
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3
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Reis PCJ, Tsuji JM, Weiblen C, Schiff SL, Scott M, Stein LY, Neufeld JD. Enigmatic persistence of aerobic methanotrophs in oxygen-limiting freshwater habitats. THE ISME JOURNAL 2024; 18:wrae041. [PMID: 38470309 PMCID: PMC11008690 DOI: 10.1093/ismejo/wrae041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 01/06/2024] [Accepted: 03/13/2024] [Indexed: 03/13/2024]
Abstract
Methanotrophic bacteria mitigate emissions of the potent greenhouse gas methane (CH4) from a variety of anthropogenic and natural sources, including freshwater lakes, which are large sources of CH4 on a global scale. Despite a dependence on dioxygen (O2) for CH4 oxidation, abundant populations of putatively aerobic methanotrophs have been detected within microoxic and anoxic waters and sediments of lakes. Experimental work has demonstrated active aerobic methanotrophs under those conditions, but how they are able to persist and oxidize CH4 under O2 deficiency remains enigmatic. In this review, we discuss possible mechanisms that underpin the persistence and activity of aerobic methanotrophs under O2-limiting conditions in freshwater habitats, particularly lakes, summarize experimental evidence for microbial oxidation of CH4 by aerobic bacteria under low or no O2, and suggest future research directions to further explore the ecology and metabolism of aerobic methanotrophs in O2-limiting environments.
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Affiliation(s)
- Paula C J Reis
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Jackson M Tsuji
- Super-cutting-edge Grand and Advanced Research (SUGAR) Program, Institute for Extra-cutting-edge Science and Technology Avant-garde Research, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa, Japan
| | - Cerrise Weiblen
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Sherry L Schiff
- Department of Earth & Environmental Sciences, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Matthew Scott
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Lisa Y Stein
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Josh D Neufeld
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
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4
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Lu J, Mu X, Zhang S, Song Y, Ma Y, Luo M, Duan R. Coupling of submerged macrophytes and epiphytic biofilms reduced methane emissions from wetlands: Evidenced by an antibiotic inhibition experiment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 904:166710. [PMID: 37652383 DOI: 10.1016/j.scitotenv.2023.166710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 08/24/2023] [Accepted: 08/28/2023] [Indexed: 09/02/2023]
Abstract
Wetlands are the largest natural methane source, but how submerged macrophytes affect methane emission remains controversial. In this study, the impacts of submerged macrophytes on methane fluxes, water purification, and epiphytic microbial community dynamics were investigated in simulated wetlands (with and without Hydrilla verticillata) treated with norfloxacin (NOR) for 24 days. Mean methane fluxes were significantly lower in treatments with Hydrilla verticillata (56.84-90.94 mg/m2/h) than bulks (65.96-113.21 mg/m2/h) (p < 0.05) during the experiment regardless of NOR. The relative conductivity (REC) values, H2O2, and malondialdehyde (MDA) contents increased in plant leaves, while water nutrients removal rates decreased with increasing NOR concentration at the same sampling time. The partial least squares path model analysis revealed that plant physiological indices and water nutrients positively affected methane fluxes (0.72 and 0.49, p < 0.001). According to illumina sequencing results of 16S rRNA and pmoA genes, α-proteobacteria (type II) and γ-proteobacteria (type I) were the dominant methanotroph classes in all epiphytic biofilms. The ratio of type I/type II methanotrophs and pmoA gene abundance in epiphytic biofilm was considerably lower in treatment with 16 mg/L NOR than without it (p < 0.05). pmoA gene abundance was negatively correlated with methane fluxes (p < 0.05). Additionally, the assembly of epiphytic bacterial community was mainly governed by deterministic processes, while stochastic dispersal limitation was the primary assembly process in the epiphytic methanotrophic community under NOR stress. The deterministic process gained more importance with time both in bacterial and methanotrophic community assembly. Network analysis revealed that relationships among bacteria in epiphytic biofilms weakened with time but associations among methanotrophic members were enhanced under NOR stress over time. It could be concluded that submerged macrophytes-epiphytic biofilms symbiotic system exhibited potential prospects to reduce methane emissions from wetlands under reasonable management.
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Affiliation(s)
- Jianhui Lu
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China
| | - Xiaoying Mu
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China
| | - Songhe Zhang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China.
| | - Yingying Song
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China
| | - Yu Ma
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China
| | - Min Luo
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China
| | - Rufei Duan
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China
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Pelsma KAJ, Verhagen DAM, Dean JF, Jetten MSM, Welte CU. Methanotrophic potential of Dutch canal wall biofilms is driven by Methylomonadaceae. FEMS Microbiol Ecol 2023; 99:fiad110. [PMID: 37698884 PMCID: PMC10561707 DOI: 10.1093/femsec/fiad110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 08/18/2023] [Accepted: 09/11/2023] [Indexed: 09/13/2023] Open
Abstract
Global urbanization of waterways over the past millennium has influenced microbial communities in these aquatic ecosystems. Increased nutrient inputs have turned most urban waters into net sources of the greenhouse gases carbon dioxide (CO2) and methane (CH4). Here, canal walls of five Dutch cities were studied for their biofilm CH4 oxidation potential, alongside field observations of water chemistry, and CO2 and CH4 emissions. Three cities showed canal wall biofilms with relatively high biological CH4 oxidation potential up to 0.48 mmol gDW-1 d-1, whereas the other two cities showed no oxidation potential. Salinity was identified as the main driver of biofilm bacterial community composition. Crenothrix and Methyloglobulus methanotrophs were observed in CH4-oxidizing biofilms. We show that microbial oxidation in canal biofilms is widespread and is likely driven by the same taxa found across cities with distinctly different canal water chemistry. The oxidation potential of the biofilms was not correlated with the amount of CH4 emitted but was related to the presence or absence of methanotrophs in the biofilms. This was controlled by whether there was enough CH4 present to sustain a methanotrophic community. These results demonstrate that canal wall biofilms can directly contribute to the mitigation of greenhouse gases from urban canals.
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Affiliation(s)
- Koen A J Pelsma
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Daniël A M Verhagen
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Joshua F Dean
- School of Geographical Sciences, University of Bristol, Bristol BS8 1SS, United Kingdom
| | - Mike S M Jetten
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Cornelia U Welte
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
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6
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Gou Y, Qin Y, Ouyang C, Zheng W, Jiang C. Research on aerobic oxidation of methane bacteria and its influencing factors in Chongqing central city section of the Yangtze River, China. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2023; 45:6435-6453. [PMID: 37322172 DOI: 10.1007/s10653-023-01631-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 05/23/2023] [Indexed: 06/17/2023]
Abstract
Bacterial communities play an important role in the carbon cycle of freshwater ecosystems. In order to understand the influencing factors of bacterial community in the process of carbon cycle and search for measures to reduce carbon emissions, Chongqing central city section of the Yangtze River and its tributaries were selected to be the study area in this research. High-throughput sequencing was applied to study aerobic oxidation of methane bacteria (MOB) in sampling area. The results showed that there were spatial differences in the community diversity of aerobic MOB in the Yangtze River in central Chongqing. The Shannon index in the sediment (2.389-2.728) was higher than that in the water (1.820-2.458), and the community diversity in the middle reaches of the main river was higher than that in the upstream and the downstream. The aerobic MOB community was mainly dominated by Type II (Methylocystis). Most of operational taxonomic units (OTUs) in the top ten had high homology with MOB from river and lake sediments, and a few OTUs had high homology with MOB from paddy fields, forests and wetland soils. The main environmental factors affecting the community structure of aerobic MOB were NH4+-N, dissolved oxygen (DO), temperature (T, p ≤ 0.001), pH (p ≤ 0.05), methane (CH4) and carbon dioxide (CO2).
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Affiliation(s)
- Yujia Gou
- Key Laboratory of Hydraulic and Waterway Engineering of the Ministry of Education, Chongqing Jiaotong University, Chongqing, 400074, China
- Chongqing Metropolitan College of Science and Technology, Chongqing, 402160, China
| | - Yu Qin
- Key Laboratory of Hydraulic and Waterway Engineering of the Ministry of Education, Chongqing Jiaotong University, Chongqing, 400074, China.
| | - Changyue Ouyang
- Key Laboratory of Hydraulic and Waterway Engineering of the Ministry of Education, Chongqing Jiaotong University, Chongqing, 400074, China
| | - Wang Zheng
- Key Laboratory of Hydraulic and Waterway Engineering of the Ministry of Education, Chongqing Jiaotong University, Chongqing, 400074, China
| | - Chengyong Jiang
- Key Laboratory of Hydraulic and Waterway Engineering of the Ministry of Education, Chongqing Jiaotong University, Chongqing, 400074, China
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7
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Ouyang C, Qin Y, Liang Y, Gou Y. Community structure and network interaction of aerobic methane-oxidizing bacteria in Chongqing's central urban area in the Three Gorges Reservoir, China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:56368-56381. [PMID: 36914933 DOI: 10.1007/s11356-023-26310-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 03/02/2023] [Indexed: 06/18/2023]
Abstract
A reservoir is an important source of methane (CH4), which is consumed by aerobic methane-oxidizing bacteria (MOB), representing the main CH4 sink in water. The central urban area of Chongqing in the Three Gorges Reservoir (TGR) area was selected as the study area in 2021. High-throughput sequencing was used to analyze the community structure and abundance of MOBs. The results showed that Methylocystis (Type II) was the dominant MOB in water, whereas Methylococcus (Type I) and Methylocystis co-dominated the sediments. High water temperature in the study area largely accounted for the predominance of Type II MOBs in the two habitats. Moreover, the influence of environmental factors on MOB community and its interspecific relationship were significantly regulated by the operation of the TGR. In the low-water-level period, NO2--N and CO2 concentration significantly correlated with Methylocystis, whereas in the high-water-level period, the higher discharge and velocity weakened the influence of all environmental factors on Methylocystis. In addition, the scouring of sediments by increasing discharge in the high-water-level period caused a significant decrease in dissolved CH4 concentration. The decrease in substrate increased interspecific competition within the MOB community, especially between different types of MOBs, in the high-water-level period.
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Affiliation(s)
- Changyue Ouyang
- School of River and Ocean Engineering, Chongqing Jiaotong University, Chongqing, 400074, China
- Key Laboratory of Hydraulic and Waterway Engineering of the Ministry of Education, Chongqing Jiaotong University, Chongqing, 400074, China
| | - Yu Qin
- School of River and Ocean Engineering, Chongqing Jiaotong University, Chongqing, 400074, China.
- Key Laboratory of Hydraulic and Waterway Engineering of the Ministry of Education, Chongqing Jiaotong University, Chongqing, 400074, China.
| | - Yue Liang
- School of River and Ocean Engineering, Chongqing Jiaotong University, Chongqing, 400074, China
| | - Yujia Gou
- School of River and Ocean Engineering, Chongqing Jiaotong University, Chongqing, 400074, China
- Key Laboratory of Hydraulic and Waterway Engineering of the Ministry of Education, Chongqing Jiaotong University, Chongqing, 400074, China
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8
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Thottathil SD, Reis PCJ, Prairie YT. Magnitude and Drivers of Oxic Methane Production in Small Temperate Lakes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:11041-11050. [PMID: 35820110 DOI: 10.1021/acs.est.2c01730] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Methanogenesis is traditionally considered as a strictly anaerobic process. Recent evidence suggests instead that the ubiquitous methane (CH4) oversaturation found in freshwater lakes is sustained, at least partially, by methanogenesis in oxic conditions. Although this paradigm shift is rapidly gaining acceptance, the magnitude and regulation of oxic CH4 production (OMP) have remained ambiguous. Based on the summer CH4 mass balance in the surface mixed layer (SML) of five small temperate lakes (surface area, SA, of 0.008-0.44 km2), we show that OMP (range of 0.01 ± 0.01 to 0.52 ± 0.04 μmol L-1 day-1) is linked to the concentrations of chlorophyll-a, total phosphorus, and dissolved organic carbon. The stable carbon isotopic mass balance of CH4 (δ13C-CH4) indicates direct photoautotrophic release as the most likely source of oxic CH4. Furthermore, we show that the oxic CH4 contribution to the SML CH4 saturation and emission is an inverse function of the ratio of the sediment area to the SML volume in lakes as small as 0.06 km2. Given that global lake CH4 emissions are dominated by small lakes (SA of <1 km2), the large contribution of oxic CH4 production (up to 76%) observed in this study suggests that OMP can contribute significantly to global CH4 emissions.
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Affiliation(s)
- Shoji D Thottathil
- Department of Environmental Science, SRM University AP, Amaravati, Mangalagiri, Andhra Pradesh 522 502, India
| | - Paula C J Reis
- Département des Sciences Biologiques, Groupe de Recherche Interuniversitaire en Limnologie, Université du Québec à Montréal, Montréal, QC H2X 1Y4, Canada
| | - Yves T Prairie
- Département des Sciences Biologiques, Groupe de Recherche Interuniversitaire en Limnologie, Université du Québec à Montréal, Montréal, QC H2X 1Y4, Canada
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9
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Ren M, Wang J. Phylogenetic divergence and adaptation of Nitrososphaeria across lake depths and freshwater ecosystems. THE ISME JOURNAL 2022; 16:1491-1501. [PMID: 35091647 PMCID: PMC9123079 DOI: 10.1038/s41396-022-01199-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Revised: 01/05/2022] [Accepted: 01/17/2022] [Indexed: 04/29/2023]
Abstract
Thaumarchaeota (now the class Nitrososphaeria in the phylum Thermoproteota in GTDB taxonomy) are abundant across marine and soil habitats; however, their genomic diversity and evolutionary history in freshwater environments remain elusive. Here, we reconstructed 17 high-quality metagenome-assembled genomes of Nitrososphaeria from a deep lake and two great rivers, and compared all available genomes between freshwater and marine habitats regarding their phylogenetic positions, relative abundance, and genomic content. We found that freshwater Nitrososphaeria were dominated by the family Nitrosopumilaceae and could be grouped into three distinct clades closely related to the genera Nitrosopumilus, Nitrosoarchaeum, and Nitrosotenuis. The Nitrosopumilus-like clade was exclusively from deep lakes, while the Nitrosoarchaeum-like clade was dominated by species from deep lakes and rivers, and the Nitrosotenuis-like clade was mainly from rivers, deep lakes, and estuaries. Interestingly, there was vertical niche separation between two clades in deep lakes, showing that the Nitrosopumilus-like species dominated shallow layers, whereas the relative abundance of the Nitrosoarchaeum-like clade increased toward deep waters. Phylogenetic clustering patterns in the Nitrosopumilaceae supported at least one freshwater-to-marine and two marine-to-freshwater transitions, the former of which refined the potential terrestrial-to-marine evolutionary path as previously proposed. The occurrence of the two marine-to-freshwater transitions were accompanied by horizontal transfer of the genes involved in nutrition regulation, osmoregulation, and cell motility during their colonization to freshwater habitats. Specifically, the Nitrosopumilus-like clade showed losses of genes encoding flagella assembly and ion transport, whereas the Nitrosoarchaeum-like clade had losses of intact genes involved in urea uptake and utilization and gains of genes encoding osmolarity-mediated mechanosensitive channels. Collectively, our results reveal for the first time the high genomic diversity of the class Nitrososphaeria across freshwater ecosystems and provide novel insights into their adaptive mechanisms and evolutionary histories.
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Affiliation(s)
- Minglei Ren
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Jianjun Wang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
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10
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Reis PCJ, Thottathil SD, Prairie YT. The role of methanotrophy in the microbial carbon metabolism of temperate lakes. Nat Commun 2022; 13:43. [PMID: 35013226 PMCID: PMC8748455 DOI: 10.1038/s41467-021-27718-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 12/07/2021] [Indexed: 11/30/2022] Open
Abstract
Previous stable isotope and biomarker evidence has indicated that methanotrophy is an important pathway in the microbial loop of freshwater ecosystems, despite the low cell abundance of methane-oxidizing bacteria (MOB) and the low methane concentrations relative to the more abundant dissolved organic carbon (DOC). However, quantitative estimations of the relative contribution of methanotrophy to the microbial carbon metabolism of lakes are scarce, and the mechanism allowing methanotrophy to be of comparable importance to DOC-consuming heterotrophy remained elusive. Using incubation experiments, microscopy, and multiple water column profiles in six temperate lakes, we show that MOB play a much larger role than their abundances alone suggest because of their larger cell size and higher specific activity. MOB activity is tightly constrained by the local methane:oxygen ratio, with DOC-rich lakes with large hypolimnetic volume fraction showing a higher carbon consumption through methanotrophy than heterotrophy at the whole water column level. Our findings suggest that methanotrophy could be a critical microbial carbon consumption pathway in many temperate lakes, challenging the prevailing view of a DOC-centric microbial metabolism in these ecosystems.
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Affiliation(s)
- Paula C J Reis
- Département des Sciences Biologiques, Groupe de Recherche Interuniversitaire en Limnologie, Université du Québec à Montréal, Montréal, QC, H2X 1Y4, Canada.
| | - Shoji D Thottathil
- Department of Environmental Science, SRM University AP, Amaravati, Andhra Pradesh, 522 502, India
| | - Yves T Prairie
- Département des Sciences Biologiques, Groupe de Recherche Interuniversitaire en Limnologie, Université du Québec à Montréal, Montréal, QC, H2X 1Y4, Canada
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11
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Pelsma KAJ, In 't Zandt MH, Op den Camp HJM, Jetten MSM, Dean JF, Welte CU. Amsterdam urban canals contain novel niches for methane-cycling microorganisms. Environ Microbiol 2021; 24:82-97. [PMID: 34863018 PMCID: PMC9299808 DOI: 10.1111/1462-2920.15864] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 12/01/2021] [Accepted: 12/01/2021] [Indexed: 01/04/2023]
Abstract
Urbanised environments have been identified as hotspots of anthropogenic methane emissions. Especially urban aquatic ecosystems are increasingly recognised as important sources of methane. However, the microbiology behind these emissions remains unexplored. Here, we applied microcosm incubations and molecular analyses to investigate the methane‐cycling community of the Amsterdam canal system in the Netherlands. The sediment methanogenic communities were dominated by Methanoregulaceae and Methanosaetaceae, with co‐occurring methanotrophic Methanoperedenaceae and Methylomirabilaceae indicating the potential for anaerobic methane oxidation. Methane was readily produced after substrate amendment, suggesting an active but substrate‐limited methanogenic community. Bacterial 16S rRNA gene amplicon sequencing of the sediment revealed a high relative abundance of Thermodesulfovibrionia. Canal wall biofilms showed the highest initial methanotrophic potential under oxic conditions compared to the sediment. During prolonged incubations the maximum methanotrophic rate increased to 8.08 mmol gDW−1 d−1 that was concomitant with an enrichment of Methylomonadaceae bacteria. Metagenomic analysis of the canal wall biofilm lead to the recovery of a single methanotroph metagenome‐assembled genome. Taxonomic analysis showed that this methanotroph belongs to the genus Methyloglobulus. Our results underline the importance of previously unidentified and specialised environmental niches at the nexus of the natural and human‐impacted carbon cycle.
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Affiliation(s)
- Koen A J Pelsma
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Heyendaalseweg 135, Nijmegen, 6525 AJ, The Netherlands.,Netherlands Earth System Science Centre, Utrecht University, Heidelberglaan 2, Utrecht, 3584 CS, The Netherlands
| | - Michiel H In 't Zandt
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Heyendaalseweg 135, Nijmegen, 6525 AJ, The Netherlands.,Netherlands Earth System Science Centre, Utrecht University, Heidelberglaan 2, Utrecht, 3584 CS, The Netherlands
| | - Huub J M Op den Camp
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Heyendaalseweg 135, Nijmegen, 6525 AJ, The Netherlands
| | - Mike S M Jetten
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Heyendaalseweg 135, Nijmegen, 6525 AJ, The Netherlands.,Netherlands Earth System Science Centre, Utrecht University, Heidelberglaan 2, Utrecht, 3584 CS, The Netherlands.,Soehngen Institute of Anaerobic Microbiology, Radboud University, Heyendaalseweg 135, Nijmegen, 6525 AJ, The Netherlands
| | - Joshua F Dean
- School of Environmental Sciences, University of Liverpool, Liverpool, L69 3GP, UK
| | - Cornelia U Welte
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Heyendaalseweg 135, Nijmegen, 6525 AJ, The Netherlands.,Soehngen Institute of Anaerobic Microbiology, Radboud University, Heyendaalseweg 135, Nijmegen, 6525 AJ, The Netherlands
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12
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Martin G, Rissanen AJ, Garcia SL, Mehrshad M, Buck M, Peura S. Candidatus Methylumidiphilus Drives Peaks in Methanotrophic Relative Abundance in Stratified Lakes and Ponds Across Northern Landscapes. Front Microbiol 2021; 12:669937. [PMID: 34456882 PMCID: PMC8397446 DOI: 10.3389/fmicb.2021.669937] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 06/30/2021] [Indexed: 11/21/2022] Open
Abstract
Boreal lakes and ponds produce two-thirds of the total natural methane emissions above the latitude of 50° North. These lake emissions are regulated by methanotrophs which can oxidize up to 99% of the methane produced in the sediments and the water column. Despite their importance, the diversity and distribution of the methanotrophs in lakes are still poorly understood. Here, we used shotgun metagenomic data to explore the diversity and distribution of methanotrophs in 40 oxygen-stratified water bodies in boreal and subarctic areas in Europe and North America. In our data, gammaproteobacterial methanotrophs (order Methylococcales) generally dominated the methanotrophic communities throughout the water columns. A recently discovered lineage of Methylococcales, Candidatus Methylumidiphilus, was present in all the studied water bodies and dominated the methanotrophic community in lakes with a high relative abundance of methanotrophs. Alphaproteobacterial methanotrophs were the second most abundant group of methanotrophs. In the top layer of the lakes, characterized by low CH4 concentration, their abundance could surpass that of the gammaproteobacterial methanotrophs. These results support the theory that the alphaproteobacterial methanotrophs have a high affinity for CH4 and can be considered stress-tolerant strategists. In contrast, the gammaproteobacterial methanotrophs are competitive strategists. In addition, relative abundances of anaerobic methanotrophs, Candidatus Methanoperedenaceae and Candidatus Methylomirabilis, were strongly correlated, suggesting possible co-metabolism. Our data also suggest that these anaerobic methanotrophs could be active even in the oxic layers. In non-metric multidimensional scaling, alpha- and gammaproteobacterial methanotrophs formed separate clusters based on their abundances in the samples, except for the gammaproteobacterial Candidatus Methylumidiphilus, which was separated from these two clusters. This may reflect similarities in the niche and environmental requirements of the different genera within alpha- and gammaproteobacterial methanotrophs. Our study confirms the importance of O2 and CH4 in shaping the methanotrophic communities and suggests that one variable cannot explain the diversity and distribution of the methanotrophs across lakes. Instead, we suggest that the diversity and distribution of freshwater methanotrophs are regulated by lake-specific factors.
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Affiliation(s)
- Gaëtan Martin
- Department of Forest Mycology and Plant Pathology, Science for Life Laboratory, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Antti J. Rissanen
- Faculty of Engineering and Natural Sciences, Tampere University, Tampere, Finland
| | - Sarahi L. Garcia
- Department of Ecology, Environment and Plant Sciences, Science for Life Laboratory, Stockholm University, Stockholm, Sweden
| | - Maliheh Mehrshad
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Moritz Buck
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Sari Peura
- Department of Forest Mycology and Plant Pathology, Science for Life Laboratory, Swedish University of Agricultural Sciences, Uppsala, Sweden
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13
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Li C, Hambright KD, Bowen HG, Trammell MA, Grossart HP, Burford MA, Hamilton DP, Jiang H, Latour D, Meyer EI, Padisák J, Zamor RM, Krumholz LR. Global co-occurrence of methanogenic archaea and methanotrophic bacteria in Microcystis aggregates. Environ Microbiol 2021; 23:6503-6519. [PMID: 34327792 DOI: 10.1111/1462-2920.15691] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 07/26/2021] [Indexed: 11/29/2022]
Abstract
Global warming and eutrophication contribute to the worldwide increase in cyanobacterial blooms, and the level of cyanobacterial biomass is strongly associated with rises in methane emissions from surface lake waters. Hence, methane-metabolizing microorganisms may be important for modulating carbon flow in cyanobacterial blooms. Here, we surveyed methanogenic and methanotrophic communities associated with floating Microcystis aggregates in 10 lakes spanning four continents, through sequencing of 16S rRNA and functional marker genes. Methanogenic archaea (mainly Methanoregula and Methanosaeta) were detectable in 5 of the 10 lakes and constituted the majority (~50%-90%) of the archaeal community in these lakes. Three of the 10 lakes contained relatively more abundant methanotrophs than the other seven lakes, with the methanotrophic genera Methyloparacoccus, Crenothrix, and an uncultured species related to Methylobacter dominating and nearly exclusively found in each of those three lakes. These three are among the five lakes in which methanogens were observed. Operational taxonomic unit (OTU) richness and abundance of methanotrophs were strongly positively correlated with those of methanogens, suggesting that their activities may be coupled. These Microcystis-aggregate-associated methanotrophs may be responsible for a hitherto overlooked sink for methane in surface freshwaters, and their co-occurrence with methanogens sheds light on the methane cycle in cyanobacterial aggregates.
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Affiliation(s)
- Chuang Li
- Department of Microbiology and Plant Biology, Institute for Energy and the Environment, The University of Oklahoma, Norman, Ok, USA
| | - K David Hambright
- Plankton Ecology and Limnology Laboratory, Program in Ecology and Evolutionary Biology, and the Geographical Ecology Group, Department of Biology, The University of Oklahoma, Norman, OK, USA
| | - Hannah G Bowen
- Department of Microbiology and Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Majoi A Trammell
- Biomedical Research Center, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Hans-Peter Grossart
- Department of Experimental Limnology, Leibniz Institute for Freshwater Ecology and Inland Fisheries, Stechlin, and Institute for Biochemistry and Biology, Potsdam University, Potsdam, Germany
| | - Michele A Burford
- Australian Rivers Institute and School of Environment and Science, Griffith University, Nathan, Qld, Australia
| | - David P Hamilton
- Australian Rivers Institute, Griffith University, Nathan, Qld, Australia
| | - Helong Jiang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China
| | - Delphine Latour
- Université Clermont Auvergne CNRS, LMGE, Aubière Cedex, France
| | - Elisabeth I Meyer
- Institute for Evolution and Biodiversity, University of Münster, Münster, Germany
| | - Judit Padisák
- Research Group of Limnology, Centre of Natural Sciences, University of Pannonia, Veszprém, Hungary
| | | | - Lee R Krumholz
- Department of Microbiology and Plant Biology, Institute for Energy and the Environment, The University of Oklahoma, Norman, Ok, USA
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14
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Rissanen AJ, Saarela T, Jäntti H, Buck M, Peura S, Aalto SL, Ojala A, Pumpanen J, Tiirola M, Elvert M, Nykänen H. Vertical stratification patterns of methanotrophs and their genetic controllers in water columns of oxygen-stratified boreal lakes. FEMS Microbiol Ecol 2021; 97:fiaa252. [PMID: 33316049 PMCID: PMC7840105 DOI: 10.1093/femsec/fiaa252] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 12/10/2020] [Indexed: 11/20/2022] Open
Abstract
The vertical structuring of methanotrophic communities and its genetic controllers remain understudied in the water columns of oxygen-stratified lakes. Therefore, we used 16S rRNA gene sequencing to study the vertical stratification patterns of methanotrophs in two boreal lakes, Lake Kuivajärvi and Lake Lovojärvi. Furthermore, metagenomic analyses were performed to assess the genomic characteristics of methanotrophs in Lovojärvi and the previously studied Lake Alinen Mustajärvi. The methanotroph communities were vertically structured along the oxygen gradient. Alphaproteobacterial methanotrophs preferred oxic water layers, while Methylococcales methanotrophs, consisting of putative novel genera and species, thrived, especially at and below the oxic-anoxic interface and showed distinct depth variation patterns, which were not completely predictable by their taxonomic classification. Instead, genomic differences among Methylococcales methanotrophs explained their variable vertical depth patterns. Genes in clusters of orthologous groups (COG) categories L (replication, recombination and repair) and S (function unknown) were relatively high in metagenome-assembled genomes representing Methylococcales clearly thriving below the oxic-anoxic interface, suggesting genetic adaptations for increased stress tolerance enabling living in the hypoxic/anoxic conditions. By contrast, genes in COG category N (cell motility) were relatively high in metagenome-assembled genomes of Methylococcales thriving at the oxic-anoxic interface, which suggests genetic adaptations for increased motility at the vertically fluctuating oxic-anoxic interface.
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Affiliation(s)
- Antti J Rissanen
- Faculty of Engineering and Natural Sciences, Tampere University, Korkeakoulunkatu 6, FI-33720, Tampere, Finland
| | - Taija Saarela
- Department of Environmental and Biological Sciences, University of Eastern Finland, Yliopistonranta 1 E, FI-70210, Kuopio, Finland
| | - Helena Jäntti
- Department of Environmental and Biological Sciences, University of Eastern Finland, Yliopistonranta 1 E, FI-70210, Kuopio, Finland
| | - Moritz Buck
- Department of Ecology and Genetics/Limnology, Uppsala University, Norbyvägen 18D, SE-75236, Uppsala, Sweden
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, box 7050, SE-75007, Uppsala, Sweden
| | - Sari Peura
- Department of Forest Mycology and Plant Pathology, Science for Life Laboratory, Swedish University of Agricultural Sciences, Almas allé 5, SE-75651, Uppsala, Sweden
| | - Sanni L Aalto
- Department of Environmental and Biological Sciences, University of Eastern Finland, Yliopistonranta 1 E, FI-70210, Kuopio, Finland
- Department of Biological and Environmental Sciences, University of Jyväskylä, Survontie 9 C, FI-40014, Jyväskylä, Finland
| | - Anne Ojala
- Ecosystems and Environment Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Viikinkaari 1, FI-00014, Helsinki, Finland
- Institute of Atmospheric and Earth System Research (INAR)/Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Viikinkaari 1, FI-00014, Helsinki, Finland
| | - Jukka Pumpanen
- Department of Environmental and Biological Sciences, University of Eastern Finland, Yliopistonranta 1 E, FI-70210, Kuopio, Finland
| | - Marja Tiirola
- Department of Biological and Environmental Sciences, University of Jyväskylä, Survontie 9 C, FI-40014, Jyväskylä, Finland
| | - Marcus Elvert
- MARUM - Center for Marine Environmental Sciences & Faculty of Geosciences, University of Bremen, Leobener Str. 8, D-28359, Bremen, Germany
| | - Hannu Nykänen
- Department of Environmental and Biological Sciences, University of Eastern Finland, Yliopistonranta 1 E, FI-70210, Kuopio, Finland
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15
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Reis PCJ, Ruiz-González C, Crevecoeur S, Soued C, Prairie YT. Rapid shifts in methanotrophic bacterial communities mitigate methane emissions from a tropical hydropower reservoir and its downstream river. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 748:141374. [PMID: 32823225 DOI: 10.1016/j.scitotenv.2020.141374] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 07/27/2020] [Accepted: 07/28/2020] [Indexed: 06/11/2023]
Abstract
Methane-oxidizing bacteria (MOB) present in the water column mitigate methane (CH4) emissions from hydropower complexes to the atmosphere. By creating a discontinuity in rivers, dams cause large environmental variations, including in CH4 and oxygen concentrations, between upstream, reservoir, and downstream segments. Although highest freshwater methanotrophic activity is often detected at low oxygen concentrations, CH4 oxidation in well-oxygenated downstream rivers below dams has also been reported. Here we combined DNA and RNA high-throughput sequencing with microscopic enumeration (by CARD-FISH) and biogeochemical data to investigate the abundance, composition, and potential activity of MOB taxa from upstream to downstream waters in the tropical hydropower complex Batang Ai (Malaysia). High relative abundance of MOB (up to 61% in 16S rRNA sequences and 19% in cell counts) and enrichment of stable isotopic signatures of CH4 (up to 0‰) were detected in the hypoxic hypolimnion of the reservoir and in the outflowing downstream river. MOB community shifts along the river-reservoir system reflected environmental sorting of taxa and an interrupted hydrologic connectivity in which downstream MOB communities resembled reservoir's hypolimnetic communities but differed from upstream and surface reservoir communities. In downstream waters, CH4 oxidation was accompanied by fast cell growth of particular MOB taxa. Our results suggest that rapid shifts in active MOB communities allow the mitigation of CH4 emissions from different zones of hydropower complexes, including in quickly re-oxygenated rivers downstream of dams.
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Affiliation(s)
- Paula C J Reis
- Département des Sciences Biologiques, Groupe de Recherche Interuniversitaire en Limnologie, Université du Québec à Montréal, Montréal, QC, Canada.
| | - Clara Ruiz-González
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar (ICM-CSIC), Barcelona, Spain
| | - Sophie Crevecoeur
- Canada Centre for Inland Waters, Water Science and Technology Branch - Watershed Hydrology and Ecology Research Division, Environment and Climate Change Canada, Burlington, ON, Canada
| | - Cynthia Soued
- Département des Sciences Biologiques, Groupe de Recherche Interuniversitaire en Limnologie, Université du Québec à Montréal, Montréal, QC, Canada
| | - Yves T Prairie
- Département des Sciences Biologiques, Groupe de Recherche Interuniversitaire en Limnologie, Université du Québec à Montréal, Montréal, QC, Canada
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16
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Guggenheim C, Freimann R, Mayr MJ, Beck K, Wehrli B, Bürgmann H. Environmental and Microbial Interactions Shape Methane-Oxidizing Bacterial Communities in a Stratified Lake. Front Microbiol 2020; 11:579427. [PMID: 33178162 PMCID: PMC7593551 DOI: 10.3389/fmicb.2020.579427] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 09/04/2020] [Indexed: 11/13/2022] Open
Abstract
In stratified lakes, methane-oxidizing bacteria (MOB) are strongly mitigating methane fluxes to the atmosphere by consuming methane entering the water column from the sediments. MOB communities in lakes are diverse and vertically structured, but their spatio-temporal dynamics along the water column as well as physico-chemical parameters and interactions with other bacterial species that drive the community assembly have so far not been explored in depth. Here, we present a detailed investigation of the MOB and bacterial community composition and a large set of physico-chemical parameters in a shallow, seasonally stratified, and sub-alpine lake. Four highly resolved vertical profiles were sampled in three different years and during various stages of development of the stratified water column. Non-randomly assembled MOB communities were detected in all compartments. We could identify methane and oxygen gradients and physico-chemical parameters like pH, light, available copper and iron, and total dissolved nitrogen as important drivers of the MOB community structure. In addition, MOB were well-integrated into a bacterial-environmental network. Partial redundancy analysis of the relevance network of physico-chemical variables and bacteria explained up to 84% of the MOB abundances. Spatio-temporal MOB community changes were 51% congruent with shifts in the total bacterial community and 22% of variance in MOB abundances could be explained exclusively by the bacterial community composition. Our results show that microbial interactions may play an important role in structuring the MOB community along the depth gradient of stratified lakes.
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Affiliation(s)
- Carole Guggenheim
- Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich - Swiss Federal Institute of Technology, Zurich, Switzerland.,Department of Surface Waters - Research and Management, Eawag - Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland
| | - Remo Freimann
- Department of Biology, Institute of Molecular Health Sciences, ETH Zurich - Swiss Federal Institute of Technology, Zurich, Switzerland
| | - Magdalena J Mayr
- Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich - Swiss Federal Institute of Technology, Zurich, Switzerland.,Department of Surface Waters - Research and Management, Eawag - Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland
| | - Karin Beck
- Department of Surface Waters - Research and Management, Eawag - Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland
| | - Bernhard Wehrli
- Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich - Swiss Federal Institute of Technology, Zurich, Switzerland.,Department of Surface Waters - Research and Management, Eawag - Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland
| | - Helmut Bürgmann
- Department of Surface Waters - Research and Management, Eawag - Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland
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